The Acquisition-Learning hypothesis
According to Krashen, there are two ways of developing language ability. Acquisition involves the subconscious acceptance of knowledge where information is stored in the brain through the use of communication; this is the process used for developing native languages. Learning, on the other hand, is the conscious acceptance of knowledge ‘about’ a language (i.e. the grammar or form). Krashen states that this is often the product of formal language instruction.